The rocket engine

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英语作文火箭怎么画

英语作文火箭怎么画Drawing a rocket in English can be an exciting and creative endeavor. Below are step-by-step instructions on how to draw a rocket, along with some tips to make your drawing stand out:Step 1: Start with the Body。

Begin by drawing the main body of the rocket. Draw a long, narrow oval shape standing upright on your paper. This oval will serve as the body or fuselage of the rocket.Step 2: Add the Fins。

Next, add fins to the bottom of the rocket. Draw three or four triangular shapes evenly spaced around the bottom edge of the oval. These fins will help stabilize the rocket as it flies through space.Step 3: Draw the Engine。

Now, draw the rocket's engine at the bottom of the oval. The engine can be a simple cone shape pointing downwards. You can add details such as lines or circles to represent the engine's components and add visual interest.Step 4: Create the Nose Cone。

英语五大短语

A，英语五大短语1,介词短语介词是学习英语的难点之一，特别在阅读过程中是一个"拦路虎"。

介词短语是构成长难句的一个重要因素。

介词短语可用作定语、状语、表语和补足语。

介词可与动词、名词、形容词等连用。

这里特别指出一种介词复合结构，with(without)构成的复合结构，这种复合结构的形式有：（一）with+名词十分词（二）with+名词+介词短语（三）with+名词+形容词（四）with+名词+动词不定式这种结构在句中起状语、定语作用，或用来对句子或某一成分作补充说明。

在这种结构中，with没有实际词意。

在翻译时可把名词和其后的介词短语或形容词当作主语和表语的关系来处理；把名词和其后的分词或动词不定式当作主语和谓语关系来处理。

(一)with+名词十分词的结构这种结构在英语中可称为"分词复合结构"。

它在句中可作定语或状语。

在科技文章中常用来对句子或某个成分作补充说明。

(1) If something is moving，with nothing touching it，it will go on forever，coasting at a uniform speed in a straight line．正在运动的某一物体，如果没有受到任何外力触动，它将永远继续作匀速直线运动。

(条件状语)(2)The light we see，with its colors ranging from deep red to deep violet，serves us in our daily lives．我们看到的从深红色到深紫色的光，在日常生活中为我们服务。

(作非限定性定语，修饰light。

)(3)With more experimenting being doing every year，much of photosythesis will certainly be known before very long．随着每年所进行的实验增多，可以肯定，不久将会对光合作用了解得更多。

engine指人的名词

engine指人的名词The corresponding English word for "engine" is "engine". It refers to a machine that uses energy to produce power or motion.1. The car's engine roared to life.汽车的引擎轰鸣着启动了。

2. The engineer examined the engine for any signs of damage.工程师检查引擎是否出现损坏的迹象。

3. The airplane engines propelled the aircraft forward.飞机的发动机将飞机推向前方。

4. I need to take my car to the mechanic because the engine is making a strange noise.我需要把车送到修理厂，因为发动机发出奇怪的声音。

5. The steam engine revolutionized transportation during the Industrial Revolution.蒸汽机在工业革命期间彻底改变了交通运输方式。

6. The ship's engines failed, leaving it stranded at sea.船舶的引擎出现故障，使其滞留在海中。

7. The train's engine pulled the cars along the tracks.火车的机车沿着轨道拖动车厢。

8. The engineer designed a more efficient engine that consumed less fuel.工程师设计了一种更高效的发动机，消耗燃料更少。

火箭起飞的英语作文

火箭起飞的英语作文Title: The Spectacle of Rocket Launch: A Marvel of Human Ingenuity。

The spectacle of a rocket launch is an awe-inspiring event that captures the essence of human ingenuity and technological advancement. From the roaring engines to the billowing plumes of smoke, each launch represents a culmination of years of scientific research, engineering expertise, and collaborative effort. Witnessing a rocket soar into the sky evokes a sense of wonder and pride in our ability to conquer the vastness of space.As the countdown begins, anticipation builds, and spectators hold their breath in anticipation of liftoff. Every second feels like an eternity as the final preparations are made, and the moment of ignition draws near. Then, with a deafening roar, the engines ignite, and the rocket begins its ascent into the heavens.The sheer power unleashed during liftoff is staggering. Rockets are propelled into space by the force of controlled explosions, harnessing the energy generated by burning fuel. The intense heat and pressure generated by these engines push the rocket against the Earth's gravitational pull, overcoming the immense forces that seek to keep it grounded.Watching a rocket ascend into the sky is a testament to human achievement and the boundless possibilities of scientific exploration. It serves as a reminder of our insatiable curiosity and our relentless pursuit of knowledge. With each launch, we push the boundaries of what is possible, venturing further into the unknown reaches of space.But the journey doesn't end with liftoff. Once therocket breaks free from the Earth's atmosphere, it entersthe vast expanse of space, where it must navigate throughthe vacuum with pinpoint precision. Onboard computers guide the rocket along its predetermined trajectory, adjusting course as necessary to ensure a successful mission.As the rocket continues on its journey, it carries with it the hopes and dreams of countless individuals who have dedicated their lives to the pursuit of space exploration. Scientists, engineers, and astronauts work tirelessly to push the boundaries of human knowledge, pushing the limits of technology to explore new frontiers.But even as we celebrate each successful launch, we are reminded of the inherent risks involved in space exploration. Every mission carries with it the potentialfor failure, and the specter of tragedy looms large. Yet, despite the dangers, we press on, driven by our innate desire to explore and discover.In conclusion, the spectacle of a rocket launch is a testament to the ingenuity, perseverance, and collaborative spirit of humanity. It represents the pinnacle of technological achievement and serves as a symbol of our boundless curiosity and ambition. As we gaze up at the stars, we are reminded of the endless possibilities thatlie beyond our world, waiting to be explored.。

jet flame翻译

jet flame翻译"Jet flame"的翻译是"射流火焰"。

下面是一些关于"jet flame"的用法和中英文对照例句：1. The jet flame of a rocket engine provides thrust for the spacecraft to travel in space.（火箭发动机的射流火焰提供了宇宙飞船在太空中的推力。

）2. The intensity of the jet flame can be adjusted to control the temperature of the metal being welded.（可以调节射流火焰的强度来控制正在焊接的金属的温度。

）3. The jet flame from the gas stove quickly heats up the water in the pot.（煤气灶上的射流火焰迅速加热了锅中的水。

）4. The firefighters used a powerful jet flame to extinguish the raging fire.（消防员使用强大的射流火焰扑灭了猛烈的大火。

）5. The jet flame of a blowtorch is often used for soldering or shaping metals.（喷灯的射流火焰通常用于焊接或塑形金属。

）6. The jet flame of a lighter is used to ignite cigarettes or candles.（打火机的射流火焰用于点燃香烟或蜡烛。

）7. The jet flame generator produces a steady stream of flames for various industrial applications.（射流火焰发生器为各种工业应用提供稳定的火焰流。

我想发明火箭作文50字

我想发明火箭作文50字英文回答：Rocket, an invention that has revolutionized space exploration and travel. It is an incredible piece of technology that has allowed us to reach for the stars and explore the unknown. The concept of a rocket is simple yet ingenious it works on the principle of Newton's third law of motion, which states that for every action, there is an equal and opposite reaction.A rocket consists of three main components: the rocket engine, the propellant, and the payload. The rocket engine is responsible for generating the thrust needed to propel the rocket forward. It does this by burning the propellant, which is a mixture of fuel and oxidizer. As the propellant burns, it produces hot gases that are expelled out of the rocket nozzle at high speeds, creating a force that pushes the rocket in the opposite direction.One of the most famous examples of a rocket is the Saturn V, which was used by NASA during the Apollo program to send astronauts to the moon. The Saturn V stood over 363 feet tall and weighed over 6 million pounds. It was powered by five F-1 engines, each capable of generating 1.5 million pounds of thrust. The sheer power of the Saturn V is mind-boggling, and it is a testament to the incredible engineering and innovation that went into its design.Rockets have not only been used for space exploration but also for various practical applications on Earth. For example, rockets are used in the military for missile defense systems and in the transportation industry for launching satellites into orbit. They have also been used in scientific research, such as studying the Earth's atmosphere or monitoring weather patterns.中文回答：火箭，一项改变了太空探索和旅行的发明。

火箭弹燃烧室强力旋压工艺流程

火箭弹燃烧室强力旋压工艺流程英文版The process of strong swirl in the combustion chamber of a rocket engine is crucial for achieving optimal performance and efficiency. This process involves the controlled injection and mixing of fuel and oxidizer, creating a turbulent flow that promotes efficient combustion. The strong swirl also helps to evenly distribute heat and pressure within the combustion chamber, reducing the risk of hot spots and ensuring a stable and reliable operation of the engine.The first step in the strong swirl process is the injection of fuel and oxidizer into the combustion chamber. This is typically done using a series of injectors positioned around the perimeter of the chamber. The injectors are designed to create a swirling motion in the flow of fuel and oxidizer, ensuring thorough mixing and efficient combustion.Once the fuel and oxidizer are injected into the combustion chamber, they are ignited to initiate the combustion process. The strong swirl created by the injectors helps to distribute the heat and pressure generated by the combustion evenly throughout the chamber, preventing localized hot spots that can lead to engine failure.As the combustion process continues, the strong swirl in the combustion chamber ensures that the fuel and oxidizer are thoroughly mixed and burned, maximizing the efficiency of the engine. The turbulent flow created by the swirl also helps to promote rapid and complete combustion, minimizing the production of harmful byproducts and maximizing the thrust generated by the engine.In conclusion, the strong swirl process in the combustion chamber of a rocket engine is essential for achieving optimal performance and efficiency. By carefully controlling the injection and mixing of fuel and oxidizer, engineers can ensure that the engine operates reliably and efficiently, providing the thrust needed for a successful launch.中文版火箭发动机燃烧室强力旋压工艺流程火箭发动机燃烧室中的强力旋压工艺对于实现最佳性能和效率至关重要。

火箭发动机自检流程

火箭发动机自检流程英文回答：Rocket Engine Self-Check Procedure.1. Pre-Flight Inspection.Verify that the engine is properly installed and secured.Check for any leaks or damage to the engine or its components.Ensure that all electrical connections are secure.Inspect the propellant lines for any leaks or blockages.2. Engine Start-Up.Open the propellant valves and ignite the engine.Monitor engine parameters (e.g., thrust, pressure, temperature) closely.Check for any abnormal sounds or vibrations.3. Engine Operation.Maintain the desired engine operating parameters (e.g., thrust, pressure, temperature).Monitor engine performance and adjust settings as necessary.Be prepared to shut down the engine if any anomalies occur.4. Engine Shutdown.Close the propellant valves and shut down the engine.Allow the engine to cool down before performing any maintenance or inspections.5. Post-Flight Inspection.Inspect the engine for any damage or wear.Check the propellant lines for any leaks or blockages.Verify that all electrical connections are secure.Additional Considerations:Always adhere to safety protocols when working with rocket engines.Use proper personal protective equipment (e.g., gloves, safety glasses).Be aware of the potential hazards associated withrocket engines (e.g., high pressure, hot exhaust).Seek expert assistance if any issues arise that cannot be resolved through the self-check procedures.中文回答：火箭发动机自检流程。

九年级英语火箭发射单选题50题

九年级英语火箭发射单选题50题1. The rocket ______ is about to be launched is named Tianwen - 1.A. whoB. whichC. whatD. where答案：B。

解析：本题考查定语从句。

先行词是“the rocket”，表示物，在定语从句中作主语，关系代词用which或者that，who用于指人，where用于指地点，what不能用于定语从句，所以选B。

2. The scientists are working hard on the project ______ will send a new rocket into orbit.A. whoB. whenC. thatD. why答案：C。

解析：先行词是“the project”，指物，在定语从句中作主语，关系代词用that或者which，who指人，when指时间，why指原因，所以这里选C。

3. A launch pad, ______ rockets are launched from, needs to be in perfect condition.A. whereB. whichC. thatD. what答案：A。

解析：先行词是“a launch pad”，表示地点，在定语从句中作状语，关系词用where，which和that在定语从句中作主语或者宾语，what不能用于定语从句，所以选A。

4. The rocket launch, ______ was broadcast live, attracted millions of viewers.A. thatB. whichC. whoD. what答案：B。

解析：先行词是“the rocket launch”，指事，在定语从句中作主语，非限制性定语从句不能用that引导，who指人，what不能用于定语从句，所以选B。

以火箭为主题的英语作文

以火箭为主题的英语作文Rockets have always been a fascinating subject for many people around the world. They symbolize human innovation, exploration, and the desire to reach new heights. In this essay, we will explore the history, technology, and future of rockets.Rockets have a long history, dating back to ancient times when they were used as weapons in warfare. The Chinese were the first to develop gunpowder rockets, which were used in battles as early as the 9th century. In the20th century, rockets played a crucial role in the space race between the United States and the Soviet Union. The launch of Sputnik 1 by the Soviet Union in 1957 marked the beginning of the space age.Rockets work on the principle of Newton's third law of motion, which states that for every action, there is an equal and opposite reaction. This means that when hot gases are expelled from the rocket engine at high speeds, the rocket is propelled in the opposite direction. Rockets can be powered by various types of fuels, such as liquid hydrogen, kerosene, or solid propellants.The technology behind rockets has evolved significantly over the years, leading to the development of powerful and efficient launch vehicles. Modern rockets are equipped with advanced guidance systems, propulsion engines, and payload delivery systems. Companies like SpaceX and NASA are constantly working on improving rocket technology to make space travel safer and more cost-effective.The future of rockets looks promising, with plans to send humans to Mars and establish a permanent presence on the Moon. These ambitious missions will require the development of new rocket designs and propulsion systems capable of traveling long distances in space. Advances in materials science and 3D printing are also expected to revolutionize rocket manufacturing processes.Overall, rockets have played a crucial role in shaping our understanding of the universe and will continue to be a key tool in our exploration of space. The possibilities are endless, and with continued innovation and collaboration, we can look forward to a future where rockets enable us to reach new frontiers in our quest for knowledge and discovery.火箭一直是世界各地许多人都感到着迷的主题。

焊接火箭心脏的作文

焊接火箭心脏的作文英文回答：Welding the heart of a rocket is a crucial and delicate task. It requires precision, expertise, and attention to detail. The heart of a rocket, also known as the rocket engine, is the most important component as it is responsible for propelling the rocket into space.I remember the first time I was tasked with welding the rocket engine. I was nervous and excited at the same time.I knew that the quality of my work would directly impact the success of the rocket launch. As I carefully positioned the pieces and started the welding process, I couldn't help but feel the weight of responsibility on my shoulders.Welding the rocket engine requires a steady hand and a keen eye. One small mistake could lead to catastrophic consequences. It's like they say, "measure twice, cut once." In my case, it was more like "weld once, launchonce." I had to ensure that every weld was perfect and that there were no defects that could compromise the integrityof the engine.After hours of meticulous work, I finally completed the welding process. I felt a sense of pride and accomplishment as I inspected my work. The rocket engine looked flawless, and I knew that it was ready to power the rocket into space.中文回答：焊接火箭的心脏是一项至关重要且细致的任务。

中考英语太空探索的历史与未来单选题40题

中考英语太空探索的历史与未来单选题40题1. Neil Armstrong is famous for being the first person to walk on the _____.A.moonB.sunC.earthD.mars答案：A。

本题考查太空探索的常识。

Neil Armstrong 是第一个登上月球的人。

B 选项太阳不能行走；C 选项地球不是Neil Armstrong 第一个行走的星球；D 选项火星目前还没有人行走过。

2. The first satellite launched into space was _____.A.Sputnik 1B.Apollo 11C.ChallengerD.Columbia答案：A。

本题考查太空探索历史中的重要事件。

Sputnik 1 是第一颗发射到太空的人造卫星。

B 选项Apollo 11 是载人登月任务；C 选项Challenger 和D 选项Columbia 都是航天飞机。

3. Who was the first American woman in space?A.Sally RideB.Judy ResnikC.Kathryn SullivanD.Mae Jemison答案：A。

本题考查太空探索中的人物。

Sally Ride 是第一位进入太空的美国女性。

B 选项Judy Resnik 也是宇航员但不是第一位美国女性宇航员；C 选项Kathryn Sullivan 也不是第一位；D 选项Mae Jemison 是第一位黑人女宇航员但不是第一位美国女性宇航员。

4. The International Space Station is a joint project of several countries. How many countries are involved?A.5B.15C.20D.25答案：B。

本题考查国际空间站的相关知识。

火箭的基本原理

火箭的基本原理The basic principle of a rocket is that it relies on Newton's third law of motion, which states that for every action, there is an equal and opposite reaction. 火箭的基本原理是依靠牛顿第三定律运动，即对于每一个动作都有一个等量但相反方向的反作用力。

When a rocket engine expels mass in one direction, it causes the rocket to move in the opposite direction. 当火箭发动机在一个方向上排出质量时，会导致火箭朝相反的方向移动。

The fuel inside the rocket is burned, and the hot gases are expelled through a nozzle at the back of the rocket. 火箭内的燃料燃烧，产生的热气体通过火箭后部的喷嘴排出。

As the gases are expelled, they create a reactive force that propels the rocket forward. 随着燃料的排出，产生的反作用力推动火箭前进。

This is the basic principle behind how a rocket is able to generate thrust and lift off from the ground. 这就是火箭产生推力并从地面升空的基本原理。

Apart from the propulsion system, the design of the rocket also plays a crucial role in its functionality. 除了推进系统外，火箭的设计也对其功能起着至关重要的作用。

The Corosync Cluster Engine

The Corosync Cluster EngineSteven C.DakeRed Hat,Inc. sdake@Christine CaulﬁeldRed Hat,Inc.ccaulfie@Andrew BeekhofNovell,Inc.abeekhof@suse.deAbstractA common cluster infrastructure called the Corosync Cluster Engine is presented.The rationale for this ef-fort as well as a history of the project are provided.The architecture is described in detail.The internal program-ming API is presented to provide developers with a basic understanding of the programming model to architec-ture mapping.Finally,examples of open source projects using the Corosync Cluster Engine are provided.1IntroductionThe Corosync Cluster Engine[Corosync]Team has designed and implemented the Corosync Cluster En-gine to meet logistical needs of the cluster commu-nity.Some members of the cluster developer commu-nity have strong desires to reduce technology and com-munity fragmentation.Technology fragmentation results in difﬁculty with in-teroperability.Different project clustering systems do not inter-operate well because they each make decisions regarding the state of the cluster in inconsistent ways. Each cluster software may take different approaches to managing failures,communicating,reading conﬁgura-tionﬁles,determining cluster membership,or recover-ing from failures.Community fragmentation results in dispersal of devel-oper talent across many different projects.Most projects have a very small set of developers.These developers in the past have not worked on the same infrastructure but instead implement code with similar functionality. This software is then is deployed in various cluster sys-tems and must be maintained and developed by individ-ual projects.The Corosync Cluster Engine resolves these issues by separating the core infrastructure from the cluster ser-vices.By making this abstraction,all cluster services can cooperate on decision making in the cluster.This abstraction also uniﬁes the core code base under one open source group with the purpose to maintain,de-velop,and direct a reusable cluster infrastructure with an OSI-approved license.2HistoryThe Corosync Cluster Engine was founded in January 2008as a reduction of the OpenAIS project.The cluster infrastructure primitives are reduced from the Service Availability Forum Application Interface Speciﬁcation APIs into a new project.This effort was spawned by various maintainers of cluster projects to improve inter-operability and unify developer talent.The OpenAIS project was founded in January2002to implement Service Availability Forum Application In-terface Speciﬁcation APIs[SaForumAIS].These APIs are designed to provide an application framework for high availability using clustering techniques to reduce MTTR[Dake05].During the development of OpenAIS, more development time was spent on the infrastructure than the APIs.As a result of the focus on the infrastruc-ture,a completely reusable plug-in based Cluster Engine was created.3Architecture3.1OverviewCorosync Cluster Engine clusters are composed of pro-cessors connected by an interconnect.This paper de-ﬁnes an interconnect as a physical communication sys-tem which allows for multicast or broadcast operation to communicate packets of information.This paper de-ﬁnes a processor as a common computer,including a CPU,memory,network interface chip,physical storage and operating system such as Linux.This type of cluster is commonly referred to as a shared-nothing cluster.•85•86•The Corosync ClusterEngineFigure 1:Corosync Cluster Engine ArchitectureThe Corosync Cluster Engine supports a fully compo-nentized plug-in architecture.Every component of the Corosync Cluster Engine can be replaced by a different component providing the same functionality at proces-sor start time.Figure 1depicts the architecture of the Corosync Cluster Engine process.The subsections in this paper are organized by depen-dency,not importance.Every component used in the Corosync Cluster Engine is critical to creating a cluster software engine.3.2Handle Database ManagerThe handle database manager provides a reference counting database that maps in O1order a unique 64-bit handle identiﬁer to a memory address.This mapping can then be used by libraries or other components of the Corosync Cluster Engine to map addresses to 64-bit val-ues.The handle database supports the creation and destruc-tion of new entries in the database.Finally,mechanisms exist to obtain a reference to the object database entry and release the reference.struct iface {void (*func1)(void);void (*func2)(void);void (*func3)(void);};/**Reference version 0of A and B interfaces */res =lcr_ifact_reference (&a_ifact_handle_ver0,"A_iface1",0,/*version 0*/&a_iface_ver0_p,(void *)0xaaaa0000);a_iface_ver0=(struct iface *)a_iface_ver0_p;res =lcr_ifact_reference (&b_ifact_handle_ver0,"B_iface1",0,/*version 0*/&b_iface_ver0_p,(void *)0xbbbb0000);b_iface_ver0=(struct iface *)b_iface_ver0_p;a_iface_ver0->func1();a_iface_ver0->func2();a_iface_ver0->func3();lcr_ifact_release (a_ifact_handle_ver0);b_iface_ver0->func1();b_iface_ver0->func2();b_iface_ver0->func3();lcr_ifact_release (b_ifact_handle_ver0);Figure 2:Example of using multiple interfaces in one applicationGarbage collection occurs automatically and a user-supplied callback may be called when the reference count for a handle reaches zero to execute destruction of the handle information.3.3Live Component ReplacementLive Component Replacement is the plug-in system used by the Corosync Cluster Engine.Every compo-nent in the engine is an LCR object which is loaded dy-namically.LCR objects are designed to be replaceable at runtime,although this feature is not yet fully imple-mented.2008Linux Symposium,V olume One•87 The LCR plug-in system is different from all other plug-in systems in that a complete C interface is plugged intothe process address space,instead of simply one func-tion call.Figure2demonstrates the use of the LCR sys-tem.LCR objects are linked statically or dynamically.When an interface is referenced,an internal storage area is checked to see if the object has been linked statically. If it has been linked statically,a reference will be given to the user.If it isn’t found in the internal storage area, the lcrso directory on the storage medium will be scanned for a matching interface.If it is found it will be loaded and referenced to the user;otherwise,an error is returned.The live component replacement plug-in system is used extensively throughout the Corosync Cluster Engine to provide dynamic run-time loading of interfaces.3.4Object DatabaseThe object database provides an in-memory non-persistent storage mechanism for the conﬁguration en-gines and service engines.The object database is a collection of objects.Every ob-ject has a name and is stored in a tree-like structure.Ev-ery object has a parent.Within objects are key and value pairs which are unique to the object.Figure3depicts a partial object database layout.The object database provides an API for the creation, deletion,and searching for objects.The database also provides mechanisms to read and write key and value pairs.Finally,the database provides a mechanism to ﬁnd objects,iterate objects within a tree,and iterate keys within an object.Objects have speciﬁc requirements.The object database allows multiple objects with the same name to be stored in the database with the same parent.Every object may contain key and value pairs.An object’s key is unique and its value is a binary blob of data.Because the object database is often used in parsing by the conﬁguration engine,a special API is provided to automatically detect failures in the storing of keys and associated values within an object.On object creation, a list of valid keys for that object can be registered as well as a validation callback for each key.If theuserof the API speciﬁes an invalid key when modifying an object within the object database,the modiﬁcation re-quest will be rejected with an error.When the key is valid,before the key is modiﬁed,the validation callback is called.This validation callback veriﬁes the contents of the value using the user-registered callback.If the callback returns an invalid value,the modiﬁcation re-quest is rejected.3.5Logging SystemA common logging system is available to service en-gines as well as the rest of the Corosync Cluster Engine software stack.The logging system is completely non-blocking and uses a separate thread in the process ad-dress space toﬁlter and output logging information.The logging system is a generically reusable library avail-able to third-party processes as well as service engines. In the case that multiple service engines use the logging system,only one thread is created by the Corosync Clus-ter Engine.The logging system supports logging with complete printf()style argument rmation may be printed to stderr,aﬁle,and/or syslog.88•The Corosync Cluster EngineA logging system may contain any number of compo-nents,called tags,which allow runtimeﬁltering of de-bug messages and8levels of tracing messages to the logging output medium.Each tracing type may be sepa-ratelyﬁltered so speciﬁc trace numbers may be used for speciﬁc functionality.A unique feature of the logging system is that a logging system and logging components are initialized through a constructor deﬁnition at the beginning of the C code for theﬁle.The conﬁguration options may also be changed at runtime.Additionally,the logging system supports the fork()system call.3.6TimersNearly every service engine requires the use of timers, so a timer system is provided.Time is represents in nanoseconds since the epoch,or January1,1970.Timers may be set to expire at an absolute time.Another type of timer allows expiration in a certain number of nanoseconds into the future.When a timer expires,it executes a callback registered at timer creation time to execute software code desired by the service engine designer.3.7The Totem StackThe Totem Single Ring Ordering and Membership Pro-tocol[Amir95]implements a totally ordered extended virtual synchrony communication model[Moser94]. Unlike many typical communication systems,the ex-tended virtual synchrony model requires that every pro-cessor agrees upon the order of messages and member-ship changes,and that those messages are completely recovered.A property of virtual synchrony,called agreed order-ing,allows for simple state synchronization of clus-ter services.Because every node receives messages in the same order,processing of messages occur once the Totem protocol has ordered the message.This allows every node in the cluster to remain in synchronization when processor failure occurs or new processors are in-cluded in the membership.One key feature of the Totem stack is that it supports the ability to communicate redundantly over multiple network interfaces.All data including the membership protocol is replicated over multiple network interfaces using the Totem Redundant Ring Protocol[Koch02].Totem is implemented completely in userspace using user datagram protocol[Postel80]multicast.The pro-tocol implementation can be conﬁgured to run within Internet Protocol version4[USC81]networks or Inter-net Protocol version6[Deering98]networks.All communication may be,at user conﬁguration,au-thenticated and encrypted using a private secret key stored securely on all nodes.3.8Conﬁguration EngineThe Corosync Cluster Engine solves the issue of con-ﬁgurationﬁle independence by providing the ability to load an application speciﬁc conﬁguration engine.The conﬁguration engine provides a method to read and write conﬁgurationﬁles in an application speciﬁc way. These plug-ins conﬁgure the Corosync Cluster Engine as well as other components speciﬁc to an application plug-in.In the event that the Corosync Cluster Engine executive is not running,the conﬁguration engine can still be used by applications transparently to read and store conﬁgu-ration information.3.9Interprocess Communication ManagerThe interprocess communication manager is responsi-ble for receipt and transmission of IPC requests.The in-coming IPC requests are routed via the service manager to the appropriate service engine plug-in.The service engine may send responses to a third-party process. Every IPC connection is an abstraction of twoﬁle de-scriptors.Oneﬁle descriptor is used for third-party process blocking request and response packets.The remainingﬁle descriptor is used exclusively for non-blocking callback operations that should be executed by the third-party process.These twoﬁle descriptors are connected to each other during initialization of the IPC connection by the Interprocess Communication Man-ager.2008Linux Symposium,V olume One•893.10Service EngineA service engine is created by third parties to provide some form of cluster wide services.Some examples of these are the Service Availability Forum’s Application Interface Speciﬁcation checkpoint service,Pacemaker, or CMAN.The service engine has a well deﬁned live component re-placement interface for run-time linking into the service manager.The service engine is responsible for provid-ing a speciﬁc class of cluster service to a user via API or external control via the interprocess communication manager.3.11Service ManagerThe service manager is responsible for loading and un-loading plug-in service engines.It is also responsible for routing all requests to the service engines loaded in the Corosync Cluster Engine.During Corosync Cluster Engine initialization,the con-ﬁguration engine is loaded.The conﬁguration engine then stores the list of service engines to load.Finally, the service manager loads every service engine.Once the service manager loads a service,it is responsi-ble for initializing the service engine.When the user re-quests an operation via the interprocess communication manager,that request is routed to the appropriate service engine by the service manager.The service manager is also responsible for sending membership changes to the service manager.A service engine replicates informa-tion via the low-level Totem Single Ring Protocol by transmitting messages.These transmitted messages are delivered via the service manager to a service engine. Finally,the service manager is responsible for routing synchronization activities with the synchronization en-gine.3.12Synchronization EngineThe synchronization engine is responsible for directing the recovery of all service engines after a failure or ad-dition of a processor.A service engine may optionally use the synchronization engine,or set the synchroniza-tion engine functions to NULL,in which case they won’t be used.typedef uint64_t cpg_handle_t; typedef enum{CPG_DISPATCH_ONE,CPG_DISPATCH_ALL,CPG_DISPATCH_BLOCKING}cpg_dispatch_t;typedef enum{CPG_TYPE_UNORDERED,CPG_TYPE_FIFO,CPG_TYPE_AGREED,CPG_TYPE_SAFE}cpg_guarantee_t;typedef enum{CPG_FLOW_CONTROL_DISABLED,CPG_FLOW_CONTROL_ENABLED}cpg_flow_control_state_t;typedef enum{CPG_OK=1,CPG_ERR_LIBRARY=2,CPG_ERR_TIMEOUT=5,CPG_ERR_TRY_AGAIN=6,CPG_ERR_INVALID_PARAM=7,CPG_ERR_NO_MEMORY=8,CPG_ERR_BAD_HANDLE=9,CPG_ERR_ACCESS=11,CPG_ERR_NOT_EXIST=12,CPG_ERR_EXIST=14,CPG_ERR_NOT_SUPPORTED=20,CPG_ERR_SECURITY=29,CPG_ERR_TOO_MANY_GROUPS=30}cpg_error_t;typedef enum{CPG_REASON_JOIN=1,CPG_REASON_LEAVE=2,CPG_REASON_NODEDOWN=3,CPG_REASON_NODEUP=4,CPG_REASON_PROCDOWN=5}cpg_reason_t;struct cpg_address{uint32_t nodeid;uint32_t pid;uint32_t reason;};#define CPG_MAX_NAME_LENGTH128 struct cpg_name{uint32_t length;char value[CPG_MAX_NAME_LENGTH]; };#define CPG_MEMBERS_MAX128Figure4.The Closed Process Group InterfaceDeﬁnitions90•The Corosync Cluster EngineThe synchronization engine has four states•sync_init•sync_process•sync_activate•sync_abortTheﬁrst step in the synchronization process for a ser-vice engine is initialization.The sync_init call in a service engine stores information for executing the re-covery algorithm created by the service engine designer. The sync_process is executed to process the recov-ery operation.Because the Totem protocol transmis-sion queue may become full on the processor executing recovery,sync_process may have to return without completing by returning a negative value.If synchro-nization was completed,a value of zero should be re-turned.If at any time during synchronization,a new processor joins the membership or a processor leaves the member-ship,the sync_abort call will be executed to reset any state created by sync_init.After synchronization has completed on all nodes, sync_activate is called to activate the new data set for the service engine.3.13Default Service EnginesThe Corosync Cluster Engine provides a few default ser-vice engines which are generically useful.Other default service engines will be provided in the future.3.13.1Closed Process Group Service EngineThe closed process group API and the associated ser-vice engine are responsible for providing closed pro-cess group messaging semantics.Closed process groups are a specialization of the process groups semantics [Birman93].Any process may join a process group.A process is a system task with a process identiﬁer,often called a PID. Once joined,a join message is sent to every process in the membership.The contents of the join message are the process ID of the process and the processor identiﬁer that the joining process on which the process is running. When the process leaves the process group,either vol-untarily,or as a result of failure,a leave message is sent to every remaining processor.The closed process group service engine allows the transmission and delivery of messages among a collec-tion of processors that have joined the process group.The deﬁnitions in Figure4and API in Figure5are used to implement the closed process group system.At all times,the extended virtual synchrony messaging model is maintained by this service.To join a process group,cpg_join()is used in a C program.The user passes the process group to join.To leave a process group,cpg_leave()is used.Failures automatically behave as if the process had executed a cpg_leave()function call.Messages are sent to every node in the process group using the C function cpg_ mcast().Changes in the process membership and delivery of messages are executed using the cpg_dispatch()C function call.This function calls the cpg_deliver_ fn_t()function to deliver messages and cpg_ confchg_fn_t()to deliver membership changes. These functions are registered during initialization with the cpg_initialize()function call.3.13.2Conﬁguration Database Service Engine The conﬁguration database service engine provides a C programming API to third-party processes to read and write conﬁguration information in the object database. The API is essentially the same as that used in the object database.The conﬁguration database service C API may operate when the Corosync Cluster Engine is not running for conﬁguration purposes.In this operational mode,a con-ﬁguration engine is loaded and automatically used to read or write the object database after the user of the C API has made changes to the object database.4Library Programming Interface4.1OverviewThe library programming interface is useful for third-party processes that wish to access a Corosync service2008Linux Symposium,V olume One•91typedef void(*cpg_deliver_fn_t)( cpg_handle_t handle,struct cpg_name*group_name,uint32_t nodeid,uint32_t pid,void*msg,int msg_len);typedef void(*cpg_confchg_fn_t)( cpg_handle_t handle,struct cpg_name*group_name,struct cpg_address*member_list,int member_list_entries, struct cpg_address*left_list,intleft_list_entries,struct cpg_address*joined_list,intjoined_list_entries);typedef struct{cpg_deliver_fn_t cpg_deliver_fn;cpg_confchg_fn_t cpg_confchg_fn;}cpg_callbacks_t;cpg_error_t cpg_initialize(cpg_handle_t*handle,cpg_callbacks_t*callbacks);cpg_error_t cpg_finalize(cpg_handle_t handle);cpg_error_t cpg_fd_get(cpg_handle_t handle,int*fd);cpg_error_t cpg_context_get(cpg_handle_t handle,void**context); cpg_error_t cpg_context_set(cpg_handle_t handle,void*context); cpg_error_t cpg_dispatch(cpg_handle_t handle,cpg_dispatch_tdispatch_types);cpg_error_t cpg_join(cpg_handle_t handle,struct cpg_name*group);cpg_error_t cpg_leave(cpg_handle_t handle,struct cpg_name*group);cpg_error_t cpg_mcast_joined(cpg_handle_t handle,cpg_guarantee_t guarantee,struct iovec*iovec,int iov_len); Figure5:The Closed Process Group Interface API engine.The library programming interface provides handle management and connection management with the hdb inline library and the cslib library.4.2Handle Database APIThe handle database API,shown in Figure6,is respon-sible for managing handles that map to memory blocks. Handle memory blocks are reference counted and the handle memory area is automatically freed when no user references the handle.The API is fully thread safe and may be used in multithreaded libraries.When creating a handle database,the function hdb_ create()should be used.When destroying a handle database,the function hdb_destroy()should be used.To create a new entry in the handle database,use the function hdb_handle_create().Once the handle is created,it will start with a reference count of1.To re-duce the reference count and free the handle,the func-tion hdb_handle_destroy()should be executed.Once a handle is created with hdb_handle_ create(),it can be referenced with hdb_handle_ get().This function will retrieve the memory storage area relating to the handle speciﬁed by the user.When the library is done using the handle,hdb_handle_ put()should be executed.4.3Corosync Library APIThe Corosync Library API,deﬁned in Figure7,pro-vides a mechanism for communicating with Corosync service engines.A library may connect with the Corosync Cluster Engine by using cslib_service_ connect().This function returns twoﬁle descriptors. Oneﬁle descriptor is used for request and response mes-sages.The remainingﬁle descriptor is used for callback data that shouldn’t block normal requests.Once an IPC connection is made,a request message can be sent with cslib_send().A response may be re-ceived with cslib_recv().These functions generally shouldn’t be used unless the size of the message to be received is variable length.When the size of the message to be received is known, cslib_send_recv()should be used.This will send a request,and receive a response of a known size.92•The Corosync Cluster Enginestruct hdb_handle{int state;void*instance;int ref_count;};struct hdb_handle_database{unsigned int handle_count;struct hdb_handle*handles;unsigned int iterator;pthread_mutex_t mutex;};void hdb_create(struct hdb_handle_database*handle_database);void hdb_destroy(struct hdb_handle_database*handle_database);int hdb_handle_create(struct hdb_handle_database*handle_database, int instance_size,unsigned int*handle_id_out);int hdb_handle_get(struct hdb_handle_database*handle_database, unsigned long long handle,void**instance);void hdb_handle_put(struct hdb_handle_database*handle_database, unsigned long long handle);void hdb_handle_destroy(struct hdb_handle_database*handle_database, unsigned long long handle);void hdb_iterator_reset(struct hdb_handle_database*handle_database);void hdb_iterator_next(struct hdb_handle_database*handle_database, void**instance,unsigned long long*handle);Figure6:The Handle Database API DeﬁnitionAll of these functions handle recovery of message trans-mission on short reads or writes,or in the event of sig-nals or other system errors that may occur.Finally,it is useful to poll aﬁle descriptor,especially in a dispatch routine.This can be achieved by using cslib_poll()which is similar to the poll system callcslib_service_connect(int*response_out,int*callback_out,unsigned int service);cslib_send(int s,const void*msg,size_t len);cslib_recv(int s,const void*sg,size_t len);cslib_send_recv(int s,struct iovec*iov,int iov_len,void*response,int response_len);cslib_poll(struct pollfd*ufds,unsigned int nfds,int timeout);Figure7:The Corosync Library API Deﬁnition except it retries on signals and other errors which are recoverable.5Service Engine Programming Model and In-terface5.1OverviewA service engine consists of a designer-supplied plug-in interface coupled with the implementation of function-ality that uses Corosync Cluster Engine APIs.A service engine designer implements the plug-in inter-face.This interface is a set of functions and data which are loaded dynamically.The service manager directs the service engine to execute functions.Some of the service engine functions then use four APIs which are registered with the service engine to execute the operations of the Corosync Cluster Engine.5.2Plug-In InterfaceThe full plug-in interface is a C structure depicted in Figure8.The interface contains both data and function2008Linux Symposium,V olume One•93calls which are used by the service manager to direct the service engine plug-in.The nameﬁeld contains a character string which uniquely identiﬁes the service engine name.Thisﬁeld is printed by the Corosync Cluster Engine to give status information to the user.The idﬁeld contains a16-bit unique identiﬁer regis-tered with the Corosync Cluster Engine.This unique identiﬁer is used to route library and Totem requests to the proper service engine by the service manager.When private data is needed to store state information, the interprocess communication manager allocates a block of memory of the size of the parameter private_ data_size during initialization of the connection.The exec_init_fnﬁeld is a function executed to ini-tialize the service engine.The exec_exit_fnﬁeld is a function executed to request the service engine to shut down.When the administrator sends a SIGUSR2signal to the Corosync Cluster Engine process,the state of the service engine is dumped to the logging system by the exec_dump_fn function.The lib_init_fnﬁeld is a function executed when a new library connection is initiated to the service en-gine by the interprocess communication manager.The lib_exit_fnﬁeld is a function executed when the IPC connection is closed by the interprocess communication manager.The main functionality of a service engine is man-aged by the service engine using the lib_engine and exec_engine parameters.These parameters contain arrays of functions which are executed by the service manager.A service engine connection is routed to the proper lib_engine function by the service manager.When a library connection requests the service engine to exe-cute functionality,the connection’s id is used to iden-tify the function in the array to execute.The lib_ engine_count contains the number of entries in the lib_engine array.The function then would generally use the various APIs available within the corosync_api_v1structure to create timers,send Totem messages,or respond with a message using the interprocess communication man-ager.When Totem messages are originated,they are deliv-ered to the proper exec_engine function by the ser-vice manager to every processor in the cluster.The proper exec_engine function is called based upon the service id in the header of the function.The exec_ engine_count contains the number of entries in the exec_engine array.The design of a service engine should take advantage of the Totem ordering guarantees by executing most of the logic of a service engine in the exec_engine func-tions.These functions generally respond to the library request that originated the Totem message using the in-terprocess communication manager API.5.3Service Engine APIs5.3.1OverviewThere are four sets of functionality within Corosync ser-vice engine APIs shown in Figure9.5.3.2Timer APIThe timer api allows a user-speciﬁed callback to be ex-ecuted when a timer expires.Timers may either be de-ﬁned as absolute or at some duration into the future.The timer_add_duration()function is used to add a callback function that expires into a certain num-ber of nanoseconds into the future.The timer_add_ absolute()function is used to execute a callback at an absolute time as speciﬁed through the number of nanoseconds since the epoch.If a timer has been added to the system,and later needs to be deleted before it expires,the designer can execute timer_delete()function to remove the timer. Finally,a service engine can obtain the system time in nanoseconds since the epoch with the timer_get() function call.5.3.3Interprocess Communication Manager API The Interprocess Communication Manager API in-cludes functions to set and determine the source of mes-sages,to obtain the IPC connection’s private data store,。

高三测试题制作纸制玩具火箭英语作文

高三测试题制作纸制玩具火箭英语作文Making a Paper Toy RocketPaper toy rockets are not only fun to make, but they also provide a great opportunity to learn about science and engineering. Today, I will guide you through the process of creating a paper toy rocket, a perfect project for high school students like us.To begin, gather all the necessary materials. You will need colored paper, scissors, tape, a straw, and a pencil. Choose a sturdy paper for the body of the rocket and a different colorfor the fins. Once you have everything ready, let's start the construction.1. Body of the Rocket:Roll the colored paper into a tube shape, ensuring that it is tight and secure.Use tape to hold the tube in place and prevent it from unraveling.At one end of the tube, create a cone shape by pinching the paper and folding it inward. This will be the tip of your rocket.2. Fins:Cut out three or four fins from the colored paper. These will help stabilize the rocket during flight.Attach the fins to the bottom of the rocket, evenly spaced apart, using tape or glue. Make sure they are aligned properlyto ensure stability.3. Rocket Engine:Take a straw and insert it into the open end of the rocket. This will serve as the rocket engine.Use a pencil to create a small hole at the base of the rocket where the straw is inserted. This will allow air to escape, propelling the rocket forward.Once your paper toy rocket is assembled, it's time for launch! Find an open outdoor space, away from any obstructions, and prepare for liftoff. Hold the rocket by the straw, aim ittowards the sky, and blow air through the straw to launch itinto the air. Watch as your creation soars through the sky, demonstrating the principles of aerodynamics and propulsion.In conclusion, creating a paper toy rocket is not only a fun and creative activity but also a valuable educational experience. By building and launching your own rocket, you can gain a deeper understanding of physics concepts and have a blast while doing so. So gather your materials, follow the steps outlined above, and let your imagination take flight with this exciting project. Happy rocketmaking!。

火箭英语作文

火箭英语作文The roar of engines, the blaze of flames, and the sheer power of thrust propelling a vehicle beyond the confines of Earth's atmosphere – the journey of a rocket is a testament to human ingenuity and the relentless pursuit of knowledge. Rockets, the vehicles designed to transport satellites, instruments, or humans into space, are marvels of modern science and engineering. Their development has enabled us to explore the vast cosmos, understand our place in the universe, and dream about the future of interstellar travel.From the early days of rocketry, with pioneers like Konstantin Tsiolkovsky, Robert H. Goddard, and Wernher von Braun, the field has evolved dramatically. These visionaries laid the groundwork for what would become a journey of epic proportions. Tsiolkovsky's equation, the rocket equation, is still used today to calculate the motion of rockets. It is given by:$$ \Delta v = I_{sp} \cdot g_0 \cdot \ln \left( \frac{m_0}{m_f} \right) $$。

有关火箭的英文介绍

有关火箭的英文介绍Rockets are vehicles that are designed to be propelled into space. They are powerful technological marvels that have revolutionized space exploration and are essential tools for travel beyond Earth's atmosphere. In this article, we will explore everything you need to know about rockets, including their basics, development, and current applications.I. Basics of RocketsRockets typically have three main parts: the engine, the fuel, and the payload. The engine generates enough thrust to propel the vehicle into space, while the fuel provides the energy required for launch. The payload is the equipment or cargothat the rocket carries into space.Additionally, rockets have several stages. Each stagehas its rocket engine and fuel, and they are discarded asthey run out of fuel. When the first stage runs out of fuel,it separates from the rest of the rocket and falls back to Earth. The second stage takes over and continues the journeyto space.II. Development of RocketsThe history of rockets dates back to ancient China, where fireworks were used in religious ceremonies. However, it was not until the 20th century that scientists began to explorethe potential of rockets for space exploration.Considerable progress in rocket technology was madeduring World War II when Germany began developing rockets.The use of rockets in warfare led to the rapid advancement of rocket technology.After the war, the United States and the Soviet Union competed in the development of rocket technology, which culminated in the space race. The Soviet Union launched the first satellite, Sputnik 1, in 1957, while the United States sent Alan Shepard into space in 1961.III. Current Applications of RocketsRockets have numerous applications in the modern world. They are used to launch satellites, space probes, and manned missions into space. They are also used for military purposes, such as missile deployment.Additionally, rockets are critical in scientific research. They enable scientists to study the behavior of celestial bodies, develop better communication systems, and explore the cosmos.Rockets are also essential for commercial applications such as tourism and space exploration. Private companies such as SpaceX, Blue Origin, and Virgin Galactic have investedvast amounts of money in the development of reusable rockets and spacecraft.ConclusionIn conclusion, rockets are an essential technology that has transformed space exploration and has numerous applications. Their development has followed a trajectory from ancientChina to modern-day aerospace companies. Further research and development will continue to shape the role of rockets in the future.。

频闪火箭原理

频闪火箭原理The principle of a frequency-modulated rocket lies in the innovative application of variable frequency technology to its propulsion system. The rocket's engine is designed to adjust the frequency of its combustion cycles, allowing for precise control of thrust and, consequently, more efficient and responsive navigation. This technology enables the rocket to adapt to changing conditions in space, optimizing its performance and enhancing mission success rates.频闪火箭的原理在于将变频技术创造性地应用于其推进系统。

火箭的发动机设计有调整燃烧周期频率的功能，从而实现对推力的精确控制，进而实现更高效、更灵活的导航。

这项技术使火箭能够适应太空中不断变化的条件，优化性能，提高任务成功率。

The core of this technology is the ability to modulate the frequency of the rocket's combustion process. By adjusting the frequency, the engine can vary the rate of fuel combustion, generating variable thrust levels. This flexibility is crucial in scenarios where rapid maneuvers or precise adjustments are required, such as avoiding debris or docking with another spacecraft.这项技术的核心是能够调制火箭燃烧过程的频率。

火箭发射英语短语

火箭发射英语短语The Launch of a Rocket: A Symphony of Science and Human Endeavor In theannals of human history, few endeavors have captured the imagination and ignited the spirit of exploration like rocket launches. These awe-inspiring feats of engineering and scientific prowess represent the culmination of countless hours of meticulous planning, rigorous testing, and unwavering determination. As a rocket ascends into the heavens, it carries with it not only its precious cargo but also the hopes and dreams of an entire planet. The countdown to a rocket launch is a crescendo of anticipation and excitement. With each tick of the clock, engineers and scientists meticulously monitor every aspect of the spacecraft and its systems, ensuring that all is in perfect order. The launchpad, a vibrant hub of activity, hums with the energy of technicians preparing the rocket for its journey into the unknown. The moment of ignition is a spectacle of raw power and primal beauty. A thunderous roar reverberates through the air as the rocket's engines ignite, sending a plume of fire and smoke billowing into the atmosphere. The spacecraft, tethered to the launchpad by an umbilical cord of cables, begins to tremble as it gathers momentum. As the rocket rises skyward, it traces an elegant arc acrossthe horizon, leaving behind a trail of condensation that stretches for miles. Spectators, their eyes fixed upon the ascending spacecraft, are filled with a sense of wonder and exhilaration. The rocket's journey is a testament to the boundless capacity of human ingenuity and the indomitable spirit of exploration. With each passing second, the rocket gains altitude, shedding its earthly bondsand venturing into the unforgiving realm of space. It navigates through layers of atmosphere, encountering increasing resistance and gravitational forces. Yet, it presses on, propelled by the unwavering thrust of its engines. Finally, therocket reaches its intended orbit, a point in space where it will perform its mission. It may be tasked with carrying satellites into orbit, conductingscientific experiments, or exploring distant planets. Whatever its purpose, the rocket's successful launch represents a triumph of human ingenuity and a pivotal moment in the advancement of our knowledge. Rocket launches are not merely technical achievements; they are also profoundly human endeavors. They embody our insatiable thirst for knowledge, our unyielding desire to push the boundaries ofthe possible, and our unwavering belief in the transformative power of exploration. Each launch is a testament to the indomitable human spirit, a beacon of hope inthe vast expanse of the cosmos.。

公共英语三级模拟题及答案解析(完整版)第十一套

The rocket engine, with its steady roar like that of a waterfall or a thunderstorm, is an impressive symbol of the new space age.Rocket engines have 1 powerful enough to shoot astronauts 2 the earth’s gravitational pull and 3 them on the moon.We have now become 4 space.Impressive and complex 5 it may appear, the rocket, which was 6 in China over 800 years 7 , is a relatively simple device.Fuel that is 8 in the rocket engine changes 9 gas.The hot and rapidly 10 gas must escape, but it can do so only 11 an opening that 12 backward.As the gas is 13 with great force, it 14 the rocket in the 15 direction. Like the kick of a gun 16 it is fired, it 17 the laws of nature 18 by Sir Isaac Newton when he discovered that“19 every action, there is 20 equal and opposite reaction.”1.A.shown B.been C.appeared D.proved2.A.against B.despite C.beyond D.from3.A.send nd C.take D.carry4.A.travelers B.astronauts C.researchers D.explorers5.A.that B.so C.as D.sometimes6.A.made B.discovered C.developed D.invented7.A.in advance B.before C.earlier D.ago8.A.round B.contained C.stored D.burned9.A.as B.into C.for D.the10.A.heating B.escaping C.expanding D.conducting11.A.in B.at C.by D.through12.A.turns B.goes C.faces D.directs13.A.transmitted B.dispersed C.erected D.radiated14.A.attracts B.leads C.pulls D.pushes15.A.same B.other C.opposite D.wrong16.A.that B.when C.if D.although17.A.states B.proves C.follows D.breaks18.A.described B.discussed C.considered D.made19.A.like B.as C.with D.for20.A.no B.an C.another D.theCloze1.【答案】D2.【答案】C【解析】根据意思判断，beyond意为“超出，超过”。

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The rocket engine, with its steady roar like that of a waterfall or a thunderstorm, is an impressive symbol of the new space age.Rocket engines have 1 powerful enough to shoot astronauts 2 the earth's gravitational pull and 3 them on the moon.We have now become 4 space.
Impressive and complex 5 it may appear, the rocket, which was 6 in China over 800 years 7 , is a relatively simple device.Fuel that is 8 in the rocket engine changes 9 gas.The hot and rapidly 10 gas must escape, but it can do so only 11 an opening that 12 backward.As the gas is 13 with great force, it 14 the rocket in the 15 direction.Like the kick of a gun 16 it is fired, it 17 the laws of nature 18 by Sir Isaac Newton when he discovered that“ 19 every action, there is 20 equal and opposite reaction.”
1.A.shown B.been C.appeared D.proved
2.A.against B.despite C.beyond D.from
3.A.send nd C.take D.carry
4.A.travelers B.astronauts C.researchers D.explorers
5.A.that B.so C.as D.sometimes
6.A.made B.discovered C.developed D.invented
7.A.in advance B.before C.earlier D.ago
8.A.round B.contained C.stored D.burned
9.A.as B.into C.for D.the
10.A.heating B.escaping C.expanding D.conducting
11.A.in B.at C.by D.through
12.A.turns B.goes C.faces D.directs
13.A.transmitted B.dispersed C.erected D.radiated
14.A.attracts B.leads C.pulls D.pushes
15.A.same B.other C.opposite D.wrong
16.A.that B.when C.if D.although
17.A.states B.proves C.follows D.breaks
18.A.described B.discussed C.considered D.made
19.A.like B.as C.with D.for
20.A.no B.an C.another D.theCloze
参考答案+解说：
1.【答案】D
【解析】因其后接形容词powerful作表语故应填系词。

shown不是系词；been和appeared虽可作系词但与句意不符；而proved可作系词，意为“证明是”，符合句意。

2.【答案】C
【解析】根据意思判断，beyond意为“超出，超过”。

3.【答案】B
【解析】因land on意为“使……着陆”,而send, take和carry表示“把……送到……上去”时,常接介词to,故应选land.
4.【答案】A
【解析】根据意思判断，travelers正确.
5.【答案】C
【解析】原句是表示让步的状语从句，而且是一个倒装句，故只能选C as。

6.【答案】D
【解析】根据词的意思区分，invented(指发明)合乎题意。

7.【答案】D
【解析】该句为which引导的定语从句，意为“中国发明火箭是在距今800多年前。

”句中谓语是一般过去时，故应选D.ago。

8.【答案】D
【解析】根据句子意思判断，burned正确。

9.【答案】B
【解析】change into是固定短语，“变成”的意思。

10.【答案】C
【解析】根据句子意思判断，应选expanding gas膨胀的气体。

11.【答案】D
【解析】through的意思为“穿过，通过”。

12.【答案】C
【解析】faces意为“朝着”。

13.【答案】D
【解析】transmit意为“传递”，disperse意为“驱散”，erect意为“直立，挺直”，radiate 意为“辐射，向各方向伸展”，只有D最合题意。

14.【答案】D
【解析】根据句子意思判断，应为push“推”。

15.【答案】C
【解析】朝相反的方向，故选C。

16.【答案】B
【解析】when引导的定语从句。

17.【答案】C
【解析】根据句子意思判断, follow在这里是遵循的意思。

18.【答案】A
【解析】根据句子意思判断，describe是“记载描述”的意思。

19.【答案】D
【解析】for是“对于”的意思。

20.【答案】B
【解析】根据上下文,只能用不定冠词an。